Screw-jack



(No Model.)

B3B. MIDDLETON.

- SCREW JACK.

Patented Jan. 29, 1884.

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WITNESSES Jaa m UNITED STATES PATENT OF ICE.

EDWARD H. mnnnnronyor PHILADELPHIA, PENNSYLVANIA.

SCREW-JACK.

SPECIFICATION forming part of Letters Patent No. 292,568, dated January 29, 1884,

' Application filed November 6, 1883. (No model.)

, useful Improvement in Screw-Jacks, which improvement is fully set forth in the following specification and accompanying drawings,

in whic Figure 1 is a side elevation of a screw-jack embodying my invention. Fig. 2 is avertical section thereof in line 00 m, Fig. 1. Fig. 3 is a view of a detached portion in line y 3 Fig. 1.

Similar letters of reference indicate corresponding parts in the several figures.

My invention consists of a stand, a nut, and worm-wheel supported onsaid stand, a screw-shaft engaging with said nut, and a Worm engaging with the worm-wheel, producing a strong, powerful, and compact screwjack.

Referring to the drawings, A represents a hollow stand formed of metal, and having on its inner'face a shoulder, a, on which is supported a nut, B.

0 represents a worm-wheel, which is cast with or secured to the upper part of the nut B, and sustained on the top edge of the stand A, it being noticedthat the nut B is sustained on the shoulder a,whereby said nut and aforesaid wheel are independently supported, the strength of the jack being accordingly increased. I

D represents a screw-shaft, which engages with the nut B and wheel C, and primarily receives the load to be elevated, said shaft having at its lower end a guide and foot, D?. which enters a vertical slot, D, in the stand, and prevents rotation of the shaft. Meshing with the worm-wheel O is a worm, E, whose shaft E ismounted'on a boss, 13, formed on or connected with the stand on the outside .thereof, and having keyed or otherwise secured to it a toothed wheel, G, with which engages a dog, H, on the loosely-fitted crankhandle J of the jack, it being noticed that said dog is pivoted to the handle J in such manner that it may be made to rotate the wheel G in opposite directions in order to raise or lower the shaft D. The handle J may, however, be firmly connected-with the shaft E, in which case the wheel G and dog H are not required.

When a wagon or other vehicle or object is to be elevated, the jack is properly located thereunder, so that the collar of the shaft D may come, in contact with the same. The handle'J is then properly operated, whereby rotation is imparted to the worm E, and consequently to the worm-wheel and nut G B. The action of the nut and worm-wheel on the -non-rotating shaft D causes the latter to rise, and thus elevate the vehicle, object, or load. By reversing the direction of rotation of the worm E by means of the handle J, the shaft D is returned and the vehicle lowered, as is evidenttionpI produce a jack which is compact, strong and durable, inexpensive, and powerful, all parts being made of metaL-excepting load is primarily received by the screw-shaft D, then transferred to the nut and worm-wheel B G, and finally received by the stand A, both nut and worm wheel bearing on said stand. The foot D protrudes sufficiently through the slot D to provide means for lifting vehicles and other objects from the bottom of the shaft D, when so required.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A screw-shaft, in combination with a nut and worm-wheel, connected as stated, a hollow stand supporting said nut and wheel, on its inner shoulder and top edge, as described, a worm mounted on the stand engaging with the worm-wheel, and an operatinghandle, substantially as and for the purpose set forth.

2. A stand, a nut and worm-wheel, a non- It will be seen that by the present construcpossibly the grip ofthe crank-handle J. The

rotating screw-shaft,a worm, and a handle, 7

operating-handle J, combined and operating EDWARD H.

Witnesses:

JOHN SHALLCROSS, CHARLES HART.

MIDDLETON.

IOC

worm, E, a toothed wheel, G, a dog, H, and

substantially as and for the purpose set forth. 

